One very popular type of tape measure has a spool which is spring loaded within a housing. A coilable tape is wrapped about the spool and extends through a slot to the outside of the housing. The end of the tape has a hook which allows it to be hooked onto the object to be measured and in addition, retains the outer end of the tape at the slot for easy grasping of the tape.
A major problem with these tapes are that when the tab breaks, the spool is then free to rotate in a direction that unwinds the spring and retracts the end into the housing. Once the end is retracted, the tape cannot be retrieved without taking the housing apart. If the housing is taken apart, the spool is displaced from its rotatably mounted position and the tape under its own spring force often uncontrollably uncoils from the spool. Because of the great difficulties in replacing a tape in the present housing and spool assemblies, one commonly throws out the tape measure when the tape breaks and buys a new one, even though the spool and housing are in perfect condition.
Attempts have been made to market a cartridge which includes a spring, spool and tape to replace the old cartridge within the old housing. See U.S. Pat. Nos. 3,716,201 issued to West on Feb. 13, 1973, and U.S. Pat. No. 3,689,004 issued to Brown and Stoutenberg on Sept. 5, 1972. However, the housing must still be taken apart to replace these cartridges. Secondly, the cost of the cartridge is comparable with buying a new tape measure. Consequently, consumers would rather spend a little extra money and obtain a new, shiny, undented housing without having any aggravation in controlling an uncoiling tape.
Furthermore, attempts have been made to adjust the spring after the cartridge has been inserted within the housing.
Many tapes have releasable lock switches that are usually slidably mounted in the front wall of the housing. However, the position at the front provides a relatively uncomfortable position and is inaccessible when the tape measure is held in a comfortable manner.
What is needed is a tape measure assembly that provides access to the spool without the need to dismount the spool from within the housing in order to replace the broken tape with a new tape. In addition, what is needed is a tape measure with an improved adjustment mechanism for adjusting the tension of the spring within the cartridge. Furthermore, a housing with a comfortably positioned and easily operable lock switch is needed.